U.S. patent number 10,648,113 [Application Number 15/609,735] was granted by the patent office on 2020-05-12 for method for washing laundry in a laundry washing machine and laundry washing machine.
This patent grant is currently assigned to Electrolux Home Products Corporation N.V.. The grantee listed for this patent is Electrolux Home Products Corporation N.V.. Invention is credited to Monica Celotto, Nicola Reid, Elisa Stabon, Maurizio Ugel, Andrea Zattin.
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United States Patent |
10,648,113 |
Zattin , et al. |
May 12, 2020 |
Method for washing laundry in a laundry washing machine and laundry
washing machine
Abstract
A method for washing laundry in a washing machine utilizes a
washing tub external to a rotatable washing drum. The method
includes providing a quantity of detergent, providing a first
quantity of water to form with the detergent a quantity of washing
solution, introducing the washing solution into the tub,
recirculating the washing solution inside the tub by recirculation
until the washing solution is absorbed by the loaded laundry inside
the drum and the level of the washing solution is below the drum,
activating a heater for heating the wetted loaded laundry inside
the drum deactivating the heater and maintaining the heated wetted
loaded laundry inside the drum for a predetermined dry maintenance
time, supplying a second quantity of water in the tub, rotating the
drum, and rinsing the loaded laundry by drum rotations and by
liquid drainage from the tub.
Inventors: |
Zattin; Andrea (Solesino,
IT), Stabon; Elisa (Gorizia, IT), Ugel;
Maurizio (Fiume Veneto, IT), Celotto; Monica
(Motta di Livenza, IT), Reid; Nicola (Budoia,
IT) |
Applicant: |
Name |
City |
State |
Country |
Type |
Electrolux Home Products Corporation N.V. |
Brussels |
N/A |
BE |
|
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Assignee: |
Electrolux Home Products
Corporation N.V. (Brussels, BE)
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Family
ID: |
46397295 |
Appl.
No.: |
15/609,735 |
Filed: |
May 31, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170260674 A1 |
Sep 14, 2017 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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14130182 |
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PCT/EP2012/062775 |
Jun 29, 2012 |
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Foreign Application Priority Data
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Jun 30, 2011 [EP] |
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11172242 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D06F
25/00 (20130101); D06F 39/04 (20130101); D06F
39/083 (20130101); D06F 35/006 (20130101); D06F
2204/02 (20130101); D06F 2204/082 (20130101); D06F
2204/086 (20130101); D06F 2204/04 (20130101) |
Current International
Class: |
D06F
39/08 (20060101); D06F 39/04 (20060101); D06F
35/00 (20060101); D06F 25/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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101173451 |
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May 2008 |
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CN |
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101696544 |
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Apr 2010 |
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CN |
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102007028212 |
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Dec 2008 |
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DE |
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1867773 |
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Dec 2007 |
|
EP |
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Other References
English translation of an Office Action dated Dec. 14, 2015 in
related Chinese Application No. 201280032692.7. cited by applicant
.
International Search Report dated Nov. 30, 2012 in corresponding
International Application No. PCT/EP2012/062775. cited by applicant
.
Extended European Search Report dated Dec. 23, 2011 in
corresponding European Application No. 11172242.7. cited by
applicant.
|
Primary Examiner: Perrin; Joseph L.
Assistant Examiner: Graf; Irina
Attorney, Agent or Firm: RatnerPrestia
Claims
The invention claimed is:
1. A method for washing laundry in a laundry washing machine
comprising a washing tub external to a rotatable washing drum
wherein the laundry to be washed is loaded, a recirculation circuit
including a recirculation pump adapted to drain liquid from a
bottom region of the washing tub and to re-admit the liquid into a
higher region of the washing tub wherein the method comprising:
providing a quantity of detergent; providing a first quantity of
water to form with said quantity of detergent a quantity of washing
solution; introducing said washing solution into said washing tub;
recirculating said washing solution inside said washing tub by said
recirculation circuit until said washing solution is absorbed by
said loaded laundry inside said washing drum and the level of said
washing solution is below said washing drum; activating a heater
for heating said wetted loaded laundry inside said washing drum;
deactivating said heater and maintaining said heated wetted loaded
laundry inside said washing drum for a predetermined dry
maintenance time; supplying a second quantity of water in said
washing tub; rotating said washing drum; and rinsing said loaded
laundry by drum rotations and by liquid drainage from said washing
tub, wherein the method further comprises a mixing phase wherein
said washing solution is mixed, the mixing phase takes place after
the phase of introducing the washing solution into the washing tub
and before the recirculating of said washing solution inside said
washing tub by the recirculation circuit, wherein said mixing phase
is carried out by a mixing device associated to the bottom of the
washing tub, said mixing device comprises: a mixing pump separate
from the recirculation circuit, an inlet connecting line separate
from the recirculation circuit, said inlet line connecting the
mixing pump to the bottom of the washing tub in a first zone
thereof, and a single outlet connecting line separate from the
recirculation circuit, said single outlet connecting line
connecting the mixing pump to the bottom of the tub in a second
zone thereof, wherein the mixing pump is activated to mix the
liquid inside the washing tub so that the mixing pump withdraws
liquid from the bottom of the washing tub via the inlet connecting
line and discharges the liquid withdrawn back into the bottom of
the tub via the single outlet connecting line.
2. The method according to claim 1, further comprising a rotation
phase of said washing drum during at least one of: recirculating
said washing solution inside said washing tub, heating said wetted
loaded laundry inside said washing drum, and maintaining said
heated wetted loaded laundry inside said washing drum for a
predetermined dry maintenance time.
3. The method according to claim 2, further comprising carrying out
a recirculating phase of liquid inside said washing tub after said
phase of supplying a second quantity of water in said washing
tub.
4. The method according to claim 2, further comprising carrying out
a further phase of providing a pre-wetting quantity of water inside
said washing tub in order to wet said loaded laundry before said
phase of introducing said washing solution into said washing
tub.
5. The method according to claim 2, wherein said heating phase
comprises heating said loaded laundry with hot air.
6. The method according to claim 1, further comprising carrying out
a recirculating phase of liquid inside said washing tub after said
phase of supplying a second quantity of water in said washing
tub.
7. The method according to claim 1, further comprising carrying out
a further phase of providing a pre-wetting quantity of water inside
said washing tub in order to wet said loaded laundry before said
phase of introducing said washing solution into said washing
tub.
8. The method according to claim 7, further comprising carrying out
a recirculating phase of water inside said washing tub after said
phase of providing a pre-wetting quantity of water.
9. The method according to claim 7, wherein said pre-wetting
quantity of water is determined based on the quantity and/or on the
type of said loaded laundry.
10. The method according to claim 7, wherein the ratio between the
sum of the pre-wetting quantity of water and the first quantity of
water and the dry weight of the loaded laundry is between 1 and 3
litres/kg.
11. The method according to claim 1, wherein said heating phase
comprises heating said loaded laundry with hot air.
12. The method according to claim 1, wherein said heating phase
comprises heating said loaded laundry with steam.
13. The method according to claim 1, wherein the ratio between said
first quantity of water and the dry weight of the loaded laundry is
between 1 and 3 litres/kg.
14. The method according to claim 1, wherein the ratio between said
second quantity of water and the dry weight of the loaded laundry
is comprised between 0.5 and 1.1 litres/kg.
Description
The present invention concerns the field of laundry washing
techniques.
In particular, the present invention refers to a method for washing
laundry in a laundry washing machine.
BACKGROUND ART
Nowadays the use of laundry washing machines, both "simple" laundry
washing machines (i.e. laundry washing machines which can only wash
and rinse laundry) and washing-drying machines (i.e. laundry
washing machines which can also dry laundry), is widespread.
In the present description the term "laundry washing machine" will
refer to both simple laundry washing machines and laundry
washing-drying machines.
Laundry washing machines generally comprise an external casing
provided with a washing tub inside which there is a rotatable
perforated drum in which the laundry is placed.
A loading/unloading door ensures access to the tub and the
drum.
Laundry washing machines typically comprise a detergent supply unit
and a water inlet circuit for the introduction of water and
washing/rinsing products (i.e. detergent, softener, etc.) into the
tub.
Known laundry washing machines are also provided with water
draining devices that may operate both during the initial phases of
the washing cycle and at the end of the same to drain the dirty
water.
In particular, a known complete washing cycle typically includes a
first laundry wetting phase with addition of the washing detergent,
a second washing phase during which the tub is rotated and the
water contained therein is heated to predetermined temperature
values based on the washing programme selected by the user, and a
final rinsing and spinning phase.
According to the known technique, the initial wetting phase
includes the step of mixing a predetermined amount of detergent
with water to form a liquor which is introduced in the tub for
wetting the laundry.
A wetting method belonging to the known technique is disclosed in
document U.S. Pat. No. 4,489,455A. In this document the wetting
phase includes first the preparation of a wash liquor in a wash
liquor reservoir. The liquor is prepared by introducing in the wash
liquor reservoir a predetermined amount of detergent composition,
which may be in granular, paste, gel or in liquid form, and a
predetermined amount of water. A proper mixing of the detergent and
of the water takes place in the reservoir by the recirculation of
the liquid from the bottom of the reservoir back into the reservoir
through connecting lines.
Recirculation of the liquid is carried out until the detergent
composition is substantially dissolved or dispersed in the
water.
The liquor is then distributed by means of a high pressure spray
nozzle as the drum rotates and the laundry is distributed about the
periphery of the movable drum.
To further enhance distribution of the detergent, wash liquor
application may be carried out in several stages, with the drum
being momentarily stopped and restarted between each stage to allow
the articles to completely redistribute themselves prior to each
stage of wash liquor application. Also, multiple spray nozzles may
be employed.
However, the method of wetting the laundry above described
belonging to the known art poses some drawbacks.
A first drawback posed by this known technique is constituted by
the fact that part of the liquor which is sprayed on the laundry
falls down in the hollow space between the drum and the tub so that
part of the detergent does not reach the laundry. Therefore a
perfect and homogeneous distribution of the detergent on the
laundry is not guaranteed.
A further drawback of the known technique is presented by the fact
that the optimum laundry/detergent ratio is not obtained.
Another drawback is presented by the fact that the distribution
phase of the liquor requires rotations of the drum with the laundry
placed therein which leads to a high electric power
consumption.
SUMMARY OF SELECTED INVENTIVE ASPECTS
An object of the present invention is therefore to overcome the
drawbacks posed by the known technique.
It is a first object of the invention to implement a washing method
that makes it possible to optimise the usage of the detergent and
to reduce the quantity of detergent used compared to the known
technique.
It is a further object of the invention to implement a washing
method that makes it possible to obtain more efficient wetting of
the laundry compared to the known technique.
It is a further object of the invention to implement a washing
method that makes it possible to reduce the water consumption
compared to the known technique.
It is a further object of the invention to implement a washing
method that makes it possible to reduce the power consumption
compared to the known technique.
The present invention therefore relates, in a first aspect thereof,
to a method for washing laundry in a laundry washing machine
comprising a washing tub external to a rotatable washing drum
wherein the laundry to be washed is loaded, the method comprising
the steps of: providing a quantity of detergent; providing a first
quantity of water to form with said quantity of detergent a
quantity of washing solution; introducing said washing solution
into said washing tub; recirculating said washing solution inside
said washing tub by means of recirculation means until said washing
solution is absorbed by said loaded laundry inside said washing
drum and the level of said washing solution is below said washing
drum; activating heating means for heating said wetted loaded
laundry inside said washing drum; deactivating said heating means
and maintain said heated wetted loaded laundry inside said washing
drum for a predetermined dry maintenance time; supplying a second
quantity of water in said washing tub; rotating said washing drum;
rinsing said loaded laundry by means of drum rotations and by means
of liquid drainage from said washing tub.
In a preferred embodiment the method comprises a rotation phase of
the washing drum during the step of recirculating the washing
solution inside the washing tub.
Preferably the method comprises a rotation phase of the washing
drum during the step of heating the wetted loaded laundry inside
the washing drum.
Advantageously the method comprises a rotation phase of the washing
drum during the step of maintaining the heated wetted loaded
laundry inside the washing drum for a predetermined dry maintenance
time.
Opportunely, the method comprises a recirculating phase of liquid
inside the washing tub after the phase of supplying a second
quantity of water in the washing tub.
In a preferred embodiment the method comprises a further phase of
providing a pre-wetting quantity of water inside the washing tub in
order to wet the loaded laundry before the phase of introducing the
washing solution into the washing tub.
Advantageously the method comprises a recirculating phase of water
inside the washing tub after the phase of providing a pre-wetting
quantity of water.
Preferably the heating phase comprises heating the loaded laundry
with hot air.
In an alternative embodiment the heating phase comprises heating
the loaded laundry with steam.
Advantageously the first quantity of water is based on the quantity
and/or on the type of the loaded laundry.
Preferably the ratio between the first quantity of water and the
dry weight of the loaded laundry is between 1 and 3 litres/kg.
Preferably the ratio is between 1.3 and 2.7 litres/kg.
Preferably the ratio is between 1.5 and 2.5 litres/kg.
Preferably the ratio is between 1.7 and 2.3 litres/kg.
Preferably the ratio is between 1.8 and 2.2 litres/kg.
Preferably the ratio is between 1.5 and 2.0 litres/kg.
More preferably the ratio between the first quantity of water and
the dry weight of the loaded laundry is between 1.5 and 1.8
litres/kg.
More preferably the ratio is between 1.5 and 1.8 litres/kg, when
the laundry 30 is substantially constituted by the "cotton base
load" as defined in the international standard IEC 60456.
Advantageously the second quantity of water is based on the
quantity and/or on the type of the loaded laundry.
Preferably the ratio between the second quantity of water and the
dry weight of the loaded laundry is between 0.5 and 1.1
litres/kg.
Preferably the ratio is between the second quantity of water and
the dry weight of the loaded laundry is between 0.7 and 0.9
litres/kg.
More preferably the ratio between the second quantity of water and
the dry weight of the loaded laundry is between 0.7 and 0.9
litres/kg, when the laundry 30 is substantially constituted by the
"cotton base load" as defined in the international standard IEC
60456. Advantageously the pre-wetting quantity of water and the
first quantity of water are stated based on the quantity and/or on
the type of the loaded laundry.
Preferably the ratio between the sum of the pre-wetting quantity of
water and the first quantity of water and the dry weight of the
loaded laundry is between 1 and 3 litres/kg.
Preferably the ratio is between 1.3 and 2.7 litres/kg.
Preferably the ratio is between 1.5 and 2.5 litres/kg.
Preferably the ratio is between 1.7 and 2.3 litres/kg.
Preferably the ratio is between 1.8 and 2.2 litres/kg.
Preferably the ratio is between 1.5 and 2.0 litres/kg.
More preferably the ratio between the sum of the pre-wetting
quantity of water and the first quantity of water and the dry
weight of the loaded laundry is between 1.5 and 1.8 litres/kg.
More preferably the ratio is between 1.5 and 1.8 litres/kg, when
the laundry 30 is substantially constituted by the "cotton base
load" as defined in the international standard IEC 60456.
Preferably the method comprises a mixing phase in which the
quantity of detergent and the first quantity of water are mixed to
form said washing solution.
Advantageously the mixing phase takes place before the phase of
introducing the washing solution into the washing tub.
In a preferred embodiment the mixing phase takes place in a drawer
of the laundry washing machine suitable to contain washing and/or
rinsing products.
In a further embodiment the mixing phase takes place in a container
suitable to receive water and to receive detergent from a drawer of
the laundry washing machine suitable to contain washing and/or
rinsing products.
In a further preferred embodiment the mixing phase takes place into
the washing tub after the phase of introducing the washing solution
into the washing tub.
Advantageously the mixing phase is carried out by means of a
recirculating device.
Opportunely, the recirculating device comprises a recirculating
circuit provided with a recirculating pump.
In an alternative embodiment the recirculating device comprises a
mixer device.
In a second aspect thereof, the present invention concerns a
laundry washing machine suited to implement the method of the
invention described above.
BRIEF DESCRIPTION OF THE DRAWINGS
Further characteristics and advantages of the present invention
will be highlighted in greater detail in the following detailed
description of some of its preferred embodiments, provided with
reference to the enclosed drawings. In said drawings:
FIG. 1 shows a front view of a laundry washing machine implementing
the method according to a first embodiment of the invention;
FIG. 2 shows a side view of the laundry washing machine shown in
FIG. 1;
FIG. 3 is a simplified flow chart of the basic operations of a
method for washing laundry in the washing machine of FIG. 1
according to a first embodiment of the invention;
FIG. 4 shows a further embodiment in relation to FIG. 3;
FIG. 5 shows a construction variant of the laundry washing machine
of FIG. 1;
FIG. 6 shows another construction variant of the laundry washing
machine of FIG. 1;
FIG. 7 shows a further embodiment in relation to FIG. 6;
FIG. 8 is a simplified flow chart of the basic operations of a
method for washing laundry in the washing machine of FIG. 7;
FIG. 9 shows a further embodiment in relation to FIG. 7;
FIG. 10 is a simplified flow chart of the basic operations of a
method for washing laundry in the washing machine of FIG. 9;
FIG. 11 shows a further embodiment in relation to FIG. 7 and
FIG. 12 is a simplified flow chart of the basic operations of a
method for washing laundry in the washing machine of FIG. 11.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS
With reference to FIG. 1 and FIG. 2, a laundry washing machine 1 is
illustrated, in which a method according to a first embodiment of
the invention is advantageously implemented.
The laundry washing machine 1 comprises an external casing or
casing 2, in which a washing tub 3 is provided that contains a
rotatable perforated drum 4, where the laundry 30 to be washed can
be loaded.
The tub 3 and the drum 4 both have preferably a substantially
cylindrical shape.
A hollow space 12 is defined between the tub 3 and the drum 4.
The casing 2 is provided with a loading/unloading door 8 which
allows access to the washing tub 3 and the drum 4.
The tub 3 is preferably suspended in a floating manner inside the
casing 2, advantageously by means of a number of coil springs and
shock-absorbers that are not illustrated herein.
The tub 3 is preferably connected to the casing 2 by means of an
elastic bellows 7, or gasket.
The drum 4 is advantageously rotated by an electric motor 11 which
preferably transmits the rotating motion to the shaft 14 of the
drum 4, advantageously by means of a belt/pulley system 13. In a
different embodiment of the invention, the motor 11 can be directly
associated with the shaft 14 of the drum 4.
A water inlet circuit 5 is arranged in the upper part of the
laundry washing machine 1 and is suited to supply water and
washing/rinsing products (i.e. detergent, softener, etc.) into the
tub 3.
The water inlet circuit 5 advantageously comprises a removable
drawer 6 provided with various compartments suited to be filled
with washing and/or rinsing products.
The water is supplied into the tub 3 by making it flow through the
drawer 6 and a supply pipe 9. The supply pipe output 9a of the
supply pipe 9 ends in correspondence of the tub 3. Preferably the
supply pipe output 9a ends in correspondence of a lateral side of
the tub 3.
In the embodiment herein described, the water is supplied into the
tub 3 by making it flow through the drawer 6.
In a preferred embodiment of the invention the inlet circuit 5
comprises a bypass duct, not illustrated, that bypasses the
compartments of the drawer 6, so as to allow supplying exclusively
water (i.e. without detergent) into the tub 3.
In an alternative embodiment of the invention, not shown, the
laundry washing machine 1 comprises a separate water supply pipe,
separated from the inlet circuit 5, adapted to supply water
directly into the tub 3.
The water inlet circuit 5 also preferably comprises a water flow
sensor, for example a flow meter, which makes it possible to
calculate the quantity of water or of the washing and/or rinsing
products supplied into the tub 3.
Laundry washing machine 1 advantageously comprises a water outlet
circuit 15.
The water outlet circuit 15 advantageously comprises a drain pump
16, a first pipe 17 connecting the tub 3 to the drain pump 16 and
an outlet pipe 18 ending outside the casing 2. The water outlet
circuit 15 is suited to drain the liquid, i.e. dirty water or water
mixed with washing and/or rinsing products, from the tub 3 to the
outside.
The water outlet circuit 15 also preferably comprises a water flow
sensor, for example a flow meter, which makes it possible to
calculate the quantity of liquid drained from the tub 3.
The water outlet circuit 15 is advantageously provided with a
recirculation circuit 216 adapted to drain liquid from a bottom
region of the tub 3 and to re-admit such a liquid into a higher
region of the tub 3.
The recirculation circuit 216 comprises the drain pump 16 and a
recirculation pipe 61. The recirculation pipe 61 advantageously
ends with a terminal nozzle 61a in an upper region of the tub 3. In
further embodiments the recirculation pipe 61 preferably ends with
a plurality of terminal nozzles and preferably at least one of the
nozzles ends in the proximity of the front door 8 and partially
arranged inside the bellows 7.
A two-way valve 65 is preferably interposed between the drain pump
16, the outlet pipe 18 and the recirculation pipe 61.
The two-way valve 65 is preferably properly controlled in order to
allow selective drainage towards the outside through the outlet
duct 18 or towards the upper region of the tub 3 through the
recirculation pipe 61.
In a further embodiment, not illustrated, the recirculation circuit
may comprise a dedicated recirculation pipe connecting a bottom
region of the tub with and higher region of the latter, and
provided with a dedicated recirculation pump; in this case the
recirculation circuit is advantageously completely separated from
the water outlet circuit.
In general, the recirculation circuit is properly realized for
transferring a portion of a liquid from a region of the tub to
another region of the tub.
The water outlet circuit 15 advantageously comprises a filtering
device, not shown in the figures, placed between the bottom of the
tub 3 and the drain pump 16 and adapted to retain all the
undesirable bodies (for example buttons that have come off the
laundry, coins erroneously introduced into the laundry washing
machine, etc.) that have passed through the holes located on the
surface of the drum 4, or fallen onto the bottom of the tub 3 while
passing in the hollow space 12 between the drum 4 and the tub 3,
which could damage or obstruct the drain pump 16.
This filtering device can preferably be removed, and then for
example cleaned, through a gate placed advantageously on the front
or back wall of the casing 2 of the laundry washing machine 1, not
shown herein; in a further embodiment, not illustrated, the
filtering device can be accessed for example by the internal of the
drum 4, for example by a suitable opening obtained therein and
selectively closed by a suitable cover, or by a removable lifter of
the drum 4.
The laundry washing machine 1 advantageously comprises a heating
device 20. In the preferred embodiment herein illustrated the
heating device 20 is a closed loop recirculation system comprising
a heating unit 20a provided with an inlet duct 20b and an output
duct 20c both communicating with the tub 3. The heating unit 20a
preferably comprises an air circulating blower and an heater
element, as for example a resistor or electric heaters. The air
circulating blower conveys the air withdrawn from the tub 3 through
the inlet duct 20b to the heater element. The air heated by the
heater element is then introduced again in the tub 3 through the
output duct 20c. The heating device 20 when activated, therefore,
recirculates and heats the air, or the humid air, inside the tub
3.
Advantageously laundry washing machine 1 comprises a temperature
sensor, not illustrated in the figures, for sensing the temperature
inside the tub 3.
The temperature sensor is advantageously used when the closed loop
system defined by the heating device 20 is activated so that the
temperature inside the tub 3 is continuously monitored and
maintained at a predetermined level.
Laundry washing machine 1 advantageously comprises a control unit
22 connected to the various parts of the laundry washing machine 1
in order to ensure its operation. The control unit 22 preferably is
connected to the water inlet circuit 5, the water outlet circuit
15, the heating device 20 and the electric motor 11 and receives
information from the various sensors provided on the laundry
washing machine 1, like the flow meter of the water inlet circuit 5
or of the outlet circuit 15, the temperature sensor, etc.
Laundry washing machine 1 advantageously comprises an interface
unit, not visible in the enclosed figures, connected to control
unit 22, accessible to the user and by means of which the user may
select and set the washing parameters, like for example a desired
washing program. Usually, other parameters can optionally be input
by the user, for example the washing temperature, the spinning
speed, the load in terms of weight of the laundry to be washed,
etc.
Based on the parameters acquired by said interface, the control
unit 22 sets and controls the various parts of the laundry washing
machine 1 in order to carry out the desired washing program.
A first embodiment of the washing method that is the subject of the
invention is described here below with reference to FIGS 1 to
3.
The laundry 30 to be washed is first placed inside the drum 4 (step
100 of FIG. 3). By operating on the interface unit the user selects
the desired washing program (step 110) depending for example on the
type and on the dirty-level of the products to wash. Furthermore,
as said before, in a preferred embodiment it is possible for the
user to input some parameters directly by the interface unit, for
example the value of the washing temperature, the rotating speed of
the drum 4 in the spinning phase, the duration of washing cycle,
etc.
Once the user has selected the desired washing program, the control
unit 22 sets the laundry washing machine 1 so that it starts the
washing cycle.
In a further embodiment, the selection of the desired washing
program (step 110) may be performed before placing the laundry 30
into the drum 4 (step 100).
In a successive phase (step 120) a quantity Qd of detergent D
together with a first quantity Q1.sub.w of water W is introduced
into the tub 3. The quantity Qd of detergent D and the first
quantity Q1.sub.w of water W form a washing solution S intended to
wet the laundry 30.
Advantageously the quantity Qs of the washing solution S, namely
the sum of the quantity Qd of detergent D and the first quantity
Q1.sub.w of water W, is a quantity Qs that does not exceed the
absorption capacity of the laundry 30, as better explained below in
the description.
It has to be noted that the quantity Qs of the washing solution S
in terms of volume, or weight, corresponds substantially to the
volume, or weigh, of the first quantity Q1.sub.w of water W. In
fact, the quantity Qd of detergent D used for the washing solution
S represents a minimal part of the washing solution S itself. For
example a typical volume ratio between the detergent D and the
washing solution S is less than 2%.
It follows that throughout the description when we state that the
quantity Qs of the washing solution S does not exceed the
absorption capacity of the laundry 30 is substantially equivalent
to state that the first quantity Q1.sub.w of water W does not
exceed the absorption capacity of the laundry 30.
The introduction of the quantity Qd of detergent D takes place
preferably through the water inlet circuit 5; the quantity Qd of
detergent D, being it powder or liquid, is preferably brought out
of the apposite compartment of the drawer 6 by the first quantity
Q1.sub.w of water W that passes through the proper compartment of
the drawer 6.
The quantity Qd of detergent D and the first quantity Q1.sub.w of
water W, i.e. the washing solution S, then flow through the supply
pipe 9 up to the supply pipe output 9a.
Preferably, all the washing solution S introduced inside the tub 3
by means of the supply pipe 9 advantageously falls down on the
bottom of the tub 3. That is guaranteed by the lateral position of
supply pipe output 9a with respect to the tub 3.
Preferably the washing solution reaches the bottom of the tub
without entering the drum and without affecting the clothes
contained inside the drum
Nevertheless a minimum quantity of the washing solution S may also
reach the laundry 30 inside the perforated drum 4.
According to the invention, during the introduction of the washing
solution S (step 120) the recirculation circuit 216 is activated
(step 130).
The washing solution S which lies on the bottom of the tub 3 is
drained towards the upper part of the tub 3 by means of the drain
pump 16. The drain pump 16 takes the washing solution S from the
bottom of the tub 3 and conveys it towards the upper part of the
tub 3 through the recirculation pipe 61 via the valve 65
opportunely driven by the control unit 22.
The washing solution S therefore flows through the recirculation
pipe 61 up to the terminal nozzle 61a and from there advantageously
reaches the laundry 30 from above.
By means of this recirculation process, uniform and complete
wetting of the laundry 30 with the washing solution S can be
accomplished.
Preferably the recirculation process takes place for a
pre-established period of time deemed sufficient to withdraw all
the washing solution S from the bottom of the tub 3 and sufficient
for its complete absorption by the laundry 30.
The complete absorption of the laundry 30 is guaranteed by the fact
that, as said before, the quantity Qs of the washing solution S is
preferably properly chosen so that it does not exceed the
absorption capacity of the laundry 30.
At the end of the recirculation process the hollow space 12 between
the tub 3 and the drum 4, therefore, is advantageously
substantially empty and free from any liquid.
More generally, at the end of the recirculation process the washing
solution S is substantially totally absorbed by the laundry 30. It
is clear that a minimum quantity of residual washing solution S may
remain on the bottom of the tub 3. In any case, the level Lr of the
residual washing solution S on the bottom of the tub 3 is
substantially below the bottom part 4a of the drum 4, as shown in
FIG. 1.
Preferably, during the introduction of the washing solution S (step
120) or/and during the recirculation phase (step 130) the drum 4 is
set rotated (step 135), so as to enhance the absorption of the
washing solution S by the laundry 30.
Rotations of the drum 4 takes place with a preferred rhythm, for
example in clockwise and/or anticlockwise direction, at a low speed
(e.g. at [10-80] rpm), and advantageously with stop interval time
between successive rotations.
In a further embodiment, the recirculation phase (step 130) may be
performed after the introduction of the washing solution S into the
tub 3 (step 120).
The first quantity Q1.sub.w of water W is preferably defined before
its introduction in the tub 3 in such a way that the washing
solution S completely wet the loaded laundry 30, as said
before.
The first quantity Q1.sub.w of water W which is introduced in the
tub 3 may be measured, during its introduction, for example by a
flow meter, not illustrated, provided in the water inlet circuit 5,
or by processing other parameters, for example the pressure of the
delivered water and the duration of the water delivery; in this way
it is possible to introduce into the tub 3 exactly the prefixed
quantity Q1.sub.w.
The first quantity Q1.sub.w of water W of the washing solution S
necessary to completely wet the laundry 30 depends mainly on the
quantity (i.e. dry weight D.sub.w) of loaded laundry 30 and on the
type of laundry 30. In fact, for example, cotton absorbs much more
water than synthetic fibres, and therefore a certain quantity of
laundry made of cotton requires, in order to be completely wetted,
much more water than a same quantity of laundry made of synthetic
fibres. The control unit 22 may be advantageously configured in
such a way to determine (e.g. to calculate by applying a prefixed
algorithm or to select among a series of memorized values) which is
the first quantity Q1.sub.w of water W of the washing solution S
necessary to completely wet the laundry 30 on the basis of the dry
weight D.sub.w of the laundry 30 and preferably also of the type of
the loaded laundry.
The ratio between the first quantity Q1.sub.w of water W and the
dry weight D.sub.w of the laundry 30 is preferably between 1 and 3
litres/kg.
Preferably this ratio Q1.sub.w/D.sub.w is between 1.3 and 2.7
litres/kg.
Preferably this ratio Q1.sub.w/D.sub.w is between 1.5 and 2.5
litres/kg.
Preferably this ratio Q1.sub.w/D.sub.w is between 1.7 and 2.3
litres/kg.
Preferably this ratio Q1.sub.w/D.sub.w is between 1.8 and 2.2
litres/kg.
Preferably this ratio Q1.sub.w/D.sub.w is between 1.5 and 2.0
litres/kg.
Preferably this ratio Q1.sub.w/D.sub.w is between 1.5 and 1.8
litres/kg.
The ratio between the first quantity Q1.sub.w of water W and the
dry weight D.sub.w of the laundry 30 is more preferably between 1.5
and 1.8 litres/kg when the laundry 30 is substantially constituted
by the "cotton base load" as defined in the international standard
IEC 60456.
The control unit 22 may also advantageously set the proper quantity
of first quantity Q1 of water W which form the quantity Qs of
washing solution S so as to obtain a suitable water-detergent ratio
value. This optimal value allows obtaining the better washing
performances. The provision of this optimal water-detergent ratio
value allows the use of a reduced quantity of detergent D with
respect to the known technique.
The dry weight D.sub.w of the laundry 30 can be obtained by the
control unit 22 in different ways.
The dry weight D.sub.w can be, for example, one of the parameters
introduced by the user when setting the washing program.
In further embodiment, the dry weight D.sub.w of the laundry 30 can
be advantageously obtained by means of suitable weight sensors
provided in the laundry washing machine 1, for example sensors that
can be associated with the shock-absorbers of the tub 3.
Again, the control unit 22 may advantageously obtain the dry weight
D.sub.w of the laundry 30 by measuring the power absorbed by the
motor 11 for the rotation of the drum 4 with the laundry 30
inserted therein. In this case, it is possible to set a brief
rotation cycle of the drum 4 before the introduction of water,
therefore with dry laundry 30, in order to measure the moment of
inertia of the laundry 30 based on the power absorbed by the
electric motor 11 and thus obtain the dry weight D.sub.w of the
laundry 30 itself by means of simple calculations.
Clearly any other method may be used to determine the quantity of
the loaded laundry 30. The type of fabric to be washed may be
advantageously communicated to the control unit 22 directly by the
user, for example by the interface unit (not illustrated), when
setting the washing program.
In another embodiment the control unit 22 may be configured in such
a way to sense or detect the type of loaded laundry by suitable
sensing/detecting means, for example optical detecting means.
Once the laundry 30 is completely wetted, a heating phase is
performed (step 140).
During this phase (step 140) the recirculation circuit 216 is
advantageously deactivated, being the hollow space 12 between the
tub 3 and the drum 4 substantially empty.
During the heating phase (step 140) the temperature Tr of the
wetted laundry 30 is increased.
The heating of the laundry 30 is advantageously carried out by the
activation of the heating device 20.
The air circulating blower of the heating unit 20a conveys the air
withdrawn from the tub 3 through the inlet duct 20b to the heater
element. The air heated by the heater element is then introduced
again in the tub 3 through the output duct 20c. The heating device
20 in this way recirculates and heats the humid air inside the tub
3.
The activation of the heating device 20, therefore, raises the
temperature of the laundry 30 to a heating temperature Tr.
The temperature Tr of the laundry 30 can be preferably estimated by
the control unit 22. For example the temperature Tr may be
estimated from the sensed air temperature T inside the tub 3 and by
knowing the dry weight D.sub.w of the laundry 30.
Clearly any other technique or method may be used to determine or
estimate the temperature Tr of the laundry 30.
In a first embodiment of the invention, the heating phase (step
140) takes place for a predetermined heating time t.sub.h.
The predetermined heating time t.sub.h is advantageously set
according to the type of loaded laundry 30 and/or the quantity of
loaded laundry 30. For example for cotton laundry, the heating time
t.sub.h may be between 1 and 30 minutes.
During the heating phase (step 140) the laundry temperature Tr is
preferably kept at a substantially constant value, for example a
constant value between 30.degree. C. and 40.degree. C., or in a
temperature range between a minimum temperature Tmin and a maximum
temperature Tmax.
The minimum temperature Tmin is preferably between 15.degree. C.
and 25.degree. C., and the maximum temperature Tmax is preferably
between 25.degree. C. and to 50.degree. C.
The predetermined temperature Tr is advantageously set according to
the type of the loaded laundry 30 and/or the quantity of loaded
laundry 30.
During the heating phase (step 140), one or more rotation cycles of
the drum 4 are also preferably performed (step 150), so as to
enhance uniform heating of the laundry 30.
In a preferred embodiment, a continuous rotation is performed,
preferably at a low rotation speed, for example between around 10
and 80 rpm.
In further embodiments, successive rotation cycles are performed at
prefixed time interval, preferably at low speed (for example around
10 and 80 rpm), with the same advantages mentioned above.
As said before, during the heating phase (step 140) the activation
of the heating device 20 raises the temperature of the laundry 30
to the heating temperature Tr.
The heating phase of the present method is advantageously obtained
with a reduced power consumption with respect the heating phase of
the known technique. In fact the energy used during the heating
phase of the present method is almost totally dissipated for
heating the water absorbed by the laundry 30. On the other hand,
the energy used for heating the liquid outside the laundry 30,
which represents a waste energy, is very low. This is
advantageously obtained thanks to the minimum quantity of residual
washing solution S which remains on the bottom of the tub 3 before
the heating phase.
Once the heating phase (step 140) has been completed, a dry
maintenance phase is started (step 155).
In this phase the heating device 20a is deactivated and the laundry
30 is kept in this condition for a predetermined dry maintenance
time td. This phase ensures that the washing solution S absorbed by
the laundry 30 has time to react with the stained fabrics of the
dirty laundry 30.
The predetermined dry maintenance time td is advantageously set
according to the type of loaded laundry 30 and/or the quantity of
loaded laundry 30 and is preferably between 10 min and 90 min. For
example for cotton laundry, the dry maintenance time t.sub.d may be
preferably between 30 min and 75 min.
During the dry maintenance phase (step 155), one or more rotation
cycles of the drum 4 are also preferably performed (step 157).
In a preferred embodiment, a continuous rotation is performed,
preferably at a low rotation speed, for example between around 10
and 80 rpm.
Once the dry maintenance phase (step 155) has been completed, a wet
maintenance phase is started (step 160).
In this phase a second quantity Q2.sub.w of water W is introduced
into the tub 3. During the wet maintenance phase (step 160), one or
more rotation cycles of the drum 4 are also preferably performed
(step 170).
The amount of liquid L.sub.q inside the tub 3 at this stage is the
sum of the quantity Qs of the washing solution S and of the second
quantity Q2.sub.w of water W. The laundry 30 is already completely
wetted from the previous phases and therefore the liquid L.sub.q
exceeds the absorption capacity of the laundry 30. Part of liquid
L.sub.q, therefore, falls down on the bottom of the tub 3.
For this reason in a further preferred embodiment, the
recirculation circuit 216 is activated (step 180) so that the
exceeding liquid on the bottom of the tub 3 can be pumped and
recirculated in the drum 4 over the laundry 30.
The introduction of the second quantity Q2.sub.w of water W
preferably takes place through the water inlet circuit 5 that will
provide for feeding water into the tub 3.
It is to be noted that the Applicant has found that the best
washing performances can be achieved when the wet maintenance phase
(step 160) does not include any heating phase, i.e. the heating
device is switched off during the wet maintenance phase (step 160).
However in other possible embodiments of the present invention the
wet maintenance phase (step 160) can comprise one or more heating
phase
Rotations of the drum 4, preferably in clockwise and/or
anticlockwise direction, advantageously takes place at a
pre-determined rotational speed, for example in a range between 10
rpm and 80 rpm.
The amount of the second quantity Q2.sub.w of water W introduced
during the wet maintenance phase (step 160) is preferably set so
that the ratio between the second quantity Q2.sub.w of water W and
the dry weight D.sub.w of the laundry 30 is between 0.5 to 1.1
litres/kg.
More preferably this ratio Q2.sub.w/D.sub.w is between 0.7 and 0.9
litres/kg.
The second quantity Q2.sub.w of water W introduced during the wet
maintenance phase helps the removal of stains from the stained
fabrics and/or the removal of the detergent D which has reacted
with the stained fabrics of the dirty laundry 30. The stains are
therefore removed from the fabrics and transferred in the water
inside the tub together with the detergent D to form a dirty liquid
solution.
Once the wet maintenance phase (step 160) has been completed, the
laundry 30 is clean and a rinsing phase is performed (step
190).
It is to be noted that during the wet maintenance phase (step 160),
the drain pump 16 and in general the drainage line is deactivated
so that the second quantity Q2.sub.w of water W is kept inside the
tub to react with the fabric and preferably is recirculated through
the tub 3 by means of the recirculation circuit 216 as described
above.
The predetermined wet maintenance time td is advantageously set
according to the type of loaded laundry 30 and/or the quantity of
loaded laundry 30 and is preferably between 10 min and 90 min. For
example for cotton laundry, the wet maintenance time td may be
preferably between 30 min and 75 min.
The rinsing phase (step 190) comprises the removal from the laundry
30 and from the tub 3 of the dirty liquid produced during the wet
maintenance phase (step 160).
The liquid on the bottom of the tub 3 is removed from the tub 3;
the removal operation preferably includes the drainage of the
liquid from the tub 3 towards the outside of the washing machine 1
by means of the drain pump 16 that takes the liquid from the bottom
of the tub 3 and conveys it towards the outside through the outlet
duct 18. The drainage of the liquid from the tub 3 towards the
outside of the washing machine 1 is advantageously performed
contemporaneously with, or after the, rotations of the drum at
higher speed, so as to extract the rinsing liquid from the laundry
30.
The rinsing phase (step 190) may preferably comprise several
consecutive cycles of the type just described.
Hence the washing program continues with a spinning phase (step
200).
The spinning phase preferably comprises one or more high-speed
rotation cycles of the drum 4 to remove from the laundry 30 as much
water as possible. The expression "high-speed" is to be interpreted
as a speed which allows removing a suitable quantity of water from
the laundry 30 by the centrifugal force; suitable values of speed
are for example from 400 rpm to 1600 rpm.
The water expelled outside the drum 4 falls down on the bottom of
the tub 3 and is removed from the tub 3 (after or contemporaneously
with the spinning phase) by means of the drain pump 16 that takes
the water from the bottom of the tub 3 and conveys it towards the
outside through the outlet duct 18.
Once the spinning phase (step 200) terminates, the washing program
is completed.
At this point, the user may take the laundry 30 out.
In case the washing program is performed in a laundry
washing-drying machine, after the spinning phase (step 200) the
laundry 30 may be advantageously subjected to a drying phase inside
the drum 4 (step 210).
FIG. 4 shows the flow chart of a further embodiment of the washing
program of the invention performed in the laundry washing machine 1
of FIGS. 1 and 2.
This method differs from the method described with reference to
FIGS. 1 and 2 for the fact that after the washing program selection
(step 110) and before the phase of introducing into the tub 3 a
quantity Qd of detergent D together with a first quantity Q1.sub.w
of water W (step 120) a further phase of pre-wetting the laundry 30
with a pre-wetting quantity Qp.sub.w of water W is provided (step
112).
This pre-wetting phase (step 112) is advantageously performed on
the base of the quantity (i.e. dry weight D.sub.w) of loaded
laundry 30 and on the type of laundry 30.
This phase (step 112) is preferably, but not necessarily, performed
when the quantity (i.e. dry weight D.sub.w) of loaded laundry 30
can be considered high.
In fact, if the dry weight D.sub.w of the loaded laundry 30 is
high, namely a load greater than half the rated-load capacity of
the laundry washing machine 1, a pre-wetting quantity Qp.sub.w of
water W is preferably introduced in one step into the tub 3 (step
112). This quantity Qp.sub.w of water W is absorbed by the laundry
30 inside the drum 4 and enhance the wetting of the high quantity
of laundry 30 before the introduction of the first quantity
Q1.sub.w of water W in the following step.
The amount of this pre-wetting quantity Qp.sub.w of water W is
calculated, or estimated, in such a way that after the successive
phase (step 120) of introducing the washing solution S, the loaded
laundry 30 is completely wetted and the level Lr of the residual
washing solution S on the bottom of the tub 3 is substantially
below the bottom part of the drum 4 or, even more preferably, the
hollow space 12 between the tub 3 and the drum 4 is substantially
empty and free from any liquid.
The amount of the pre-wetting quantity Qp.sub.w of water W is
preferably set so that the ratio (Qp.sub.w+Q1.sub.w)/D.sub.w
between the sum Qp.sub.w+Q1.sub.w of the pre-wetting quantity
Qp.sub.w of water W and the first quantity Q1.sub.w and the dry
weight D.sub.w of the laundry 30 is between 1 and 3 litres/kg.
Preferably this ratio (Qp.sub.w+Q1.sub.w)/D.sub.w is between 1.3
and 2.7 litres/kg.
Preferably this ratio (Qp.sub.w+Q1.sub.w)/D.sub.w is between 1.5
and 2.5 litres/kg.
Preferably this ratio (Qp.sub.w+Q1.sub.w)/D.sub.w is between 1.7
and 2.3 litres/kg.
Preferably this ratio (Qp.sub.w+Q1.sub.w)/D.sub.w is between 1.8
and 2.2 litres/kg.
Preferably this ratio (Qp.sub.w+Q1.sub.w)/D.sub.w is between 1.5
and 2.0 litres/kg.
The amount of the pre-wetting quantity Qp.sub.w of water W is
preferably set so that the ratio (Qp.sub.w+Q1.sub.w)/D.sub.w
between the sum Qp.sub.w+Q1.sub.w of the pre-wetting quantity
Qp.sub.w of water W and the first quantity Q1.sub.w and the dry
weight D.sub.w of the laundry 30 is between 1.5 and 1.8 litres/kg
when the laundry 30 is substantially constituted by the "cotton
base load" as defined in the international standard IEC 60456.
The complete absorption of the laundry 30 is guaranteed by the fact
that the sum of the pre-wetting quantity Qp.sub.w of water W and
the quantity Qs of the washing solution S is properly chosen so
that it does not exceed the absorption capacity of the laundry
30.
This phase (step 112) is also preferably performed on the base of
the type of the laundry 30, for example if the laundry is made of
cotton it will require a higher quantity of water than a load of
synthetic laundry.
During the introduction of the pre-wetting quantity Qp.sub.w of
water W (step 112) the recirculation circuit 216 is advantageously
activated (step 114).
The water W which lies on the bottom of the tub 3 is drained
towards the upper part of the tub 3 by means of the drain pump 16
and reaches the laundry 30 from above.
By means of this recirculation process, uniform and complete
wetting of the laundry 30 with the pre-wetting quantity Qp.sub.w of
water W can be accomplished.
Preferably, the recirculation process takes place for a
pre-established period of time deemed sufficient for the complete
absorption of the pre-wetting quantity Qp.sub.w of water W by the
laundry 30.
It has to be noted that the quantity Qp.sub.w of water W of the
pre-wetting phase (step 112) here disclosed has to be considered
the quantity of water that wet the laundry 30 before the phase of
introducing into the tub 3 a quantity Qd of detergent D together
with a first quantity Q1.sub.w of water W (step 120).
In the embodiment above described, the quantity Qp.sub.w of water W
has been provided by introducing it in one step into the tub 3.
Nevertheless, the pre-wetting phase (step 112) may be differently
performed by comprising further steps of introducing water into the
tub 3 and draining water from the tub 3. This steps may
advantageously enhance and render more uniform the absorption of
water by the laundry 30. Spinning steps may also advantageously be
provided between said steps of introducing and draining water. In
any case, the quantity of the remaining water which wets the
laundry at the end of pre-wetting phase (step 112) represents the
pre-wetting quantity Qp.sub.w of water before the successive
introducing phase (step 120).
The quantity of this remaining water, i.e. the pre-wetting quantity
Qp.sub.w, may be easily calculated by the control unit through the
measurement of the water introduced in the tub 3 and the water
drained from the tub during the pre-wetting phase (step 112).
FIG. 5 shows a construction variant washing machine 101
implementing the method of the invention.
This washing machine 101 differs from the washing machine 1 shown
in FIG. 1 for the fact that the heating device 120 comprises a
steam supply device instead of a closed loop hot air recirculation
system.
The steam supply device 120 is construed to supply a predetermined
amount of steam into the tub 3 by evaporating water using
high-temperature hot air. The steam supply device 120 comprises a
heating unit 120a for generating high-temperature hot air to
evaporate water coming from a water supply pipe 120b. It also
comprises a steam supply pipe 120c through which steam generated
from the water evaporation by the heating unit 120a flows.
The steam supply pipe 120c advantageously ends with a terminal
nozzle 120d in an upper region of the tub 3.
The steam supply device 120 when activated, therefore, introduces
hot and humid air inside the tub 3 and allows heating of the loaded
laundry 30.
FIG. 6 shows a construction variant washing machine 201
implementing the method of the invention.
This washing machine 201 differs from the washing machine 1 shown
in FIG. 1 for the fact that it comprises a device 19 suited to
sense (or detect) the water level L inside the tub 3.
The device 19 preferably comprises a pressure sensor which senses
the pressure in the tub 3, which value is related to the level of
free water contained in the tub 3. In another embodiment, not
illustrated, laundry washing machine 1 comprises (in addition to or
as a replacement of the pressure sensor) a level sensor (for
example mechanical, electro-mechanical, optical, etc.) adapted to
sense (or detect) the water level inside the tub 3.
The provision of the device 19 simplifies the phase of introducing
water W inside the tub 3 to wet completely the laundry 30.
With this device 19 the necessity of determining in advance the
first quantity Q1.sub.w of water W to be introduced in the tub 3 to
wet completely the loaded laundry 30 is avoided.
In fact, the phase of introducing water W in the tub 3 (step 120)
with the recirculation circuit 216 active (step 130) is carried out
by slowly adding water W in the tub 3 from the inlet circuit 5
until a pre-fixed minimum level L1 of liquid is detected from the
device 19.
If the liquid level L is below the minimum level L1 it means that
the water introduced in the tub 3 is totally absorbed by the
laundry 30 and more water is necessary to wet completely the
laundry 30.
If the water level L reach the minimum level L1 it means that the
laundry 30 is completely wetted and the introduction of water W in
the tub 3 may be interrupted and hence the introducing phase (step
120) may be considered terminated.
After this phase (step 120) the water level L is substantially at
the minimum level L1 which is below the bottom part 4a of the drum
4. The hollow space 12 between the tub 3 and the drum 4 is empty
and free from any liquid, as shown in FIG. 6, and a minimum
quantity of liquid is present on the first pipe 17 of the outlet
circuit 15.
FIG. 7 shows a construction variant washing machine 301
implementing a further embodiment of the method of the
invention.
This washing machine 301 differs from the washing machine 201 shown
in FIG. 6 for the fact that it comprises a mixing device 32 which
is applied to the removable drawer 6.
The mixing device 32 is applied to a mixing compartment 6a of the
removable drawer 6 and comprises a recirculation mixing pump 32a,
an inlet connecting line 32b connecting the recirculation mixing
pump 32a to the mixing compartment 6a and an outlet connecting line
32c connecting the recirculation mixing pump 32a to the mixing
compartment 6a.
The recirculation mixing pump 32a is activated to recirculate the
liquid inside the mixing compartment 6a. The recirculation mixing
pump 32a withdraws liquid from the bottom of the mixing compartment
6a via the inlet connecting line 32b and discharges the liquid
withdrawn back into the mixing compartment 6a via the outlet
connecting line 32c.
Advantageously when the mixing compartment 6a contains detergent D
and water W, the recirculation process allows the preparation of a
more uniform washing solution S wherein the detergent D is properly
dissolved or dispersed in the water W.
FIG. 8 shows the flow chart of the washing program of the invention
performed in the washing machine 301 of FIG. 7.
The initial phases of the washing program of loading the laundry 30
(step 100) and of the washing program selection (step 110) are the
same as described above.
In a successive phase (step 116) a quantity Qd of detergent D
together with a first quantity Q1.sub.w of water W is introduced
into the mixing compartment 6a of the drawer 6. The quantity Qd of
detergent D and the first quantity Q1.sub.w of water W form the
washing solution S intended to wet the laundry 30, as previously
explained in the description.
After the introduction of the detergent D and of the water W in the
mixing compartment 6a, the recirculation mixing pump 32a is
activated to recirculate the liquid inside the mixing compartment
6a in order to prepare a uniform washing solution S (step 118).
The washing solution S is then introduced in the tub 3 (step 120)
through the supply pipe 9 and the washing program may continue with
the following phases as described above with reference to the flow
chart of FIG. 3.
In further embodiments the washing solution S may be prepared in
successive steps introducing successive quantities of detergent
and/or successive quantities of water into the mixing compartment
6a. It is clear that at the end of the successive steps, the sum of
the quantities of detergent introduced in the mixing compartment 6a
corresponds to the quantity Qd and the sum of the quantities of
water introduced in the mixing compartment 6a corresponds to the
first quantity Q1.sub.w.
FIG. 9 shows a construction variant washing machine 401 of the
laundry washing machine of FIG. 7.
This washing machine 401, as the washing machine 301 shown in FIG.
7, allows the preparation of a properly mixed washing solution S
before its introduction in the tub 3.
The washing machine 401 comprises a mixing device 42 which is
associated to the removable drawer 6.
The mixing device 42 comprises a mixing tank 43 connected to the
removable drawer 6 by an input supply pipe 44, a recirculation
mixing pump 42a, an inlet connecting line 42b connecting the
recirculation mixing pump 42a to the mixing tank 43, an outlet
connecting line 42c connecting the recirculation mixing pump 42a to
the mixing tank 43 and an output conveying pipe 45 connecting the
mixing tank 43 to the tub 3.
The mixing tank 43 is supplied with a quantity Qd of detergent D
and with a first quantity Q1.sub.w of water W by means of the
supply pipe 44 which selectively withdraws detergent D and/or water
W from the removable drawer 6.
The recirculation mixing pump 42a is activated to recirculate the
liquid inside the mixing tank 43. The recirculation mixing pump 42a
withdraws liquid from the bottom of the mixing tank 43 via the
inlet connecting line 42b and discharges the liquid withdrawn back
into the mixing tank 43 via the outlet connecting line 42c.
Advantageously the recirculation process allows the preparation of
a uniform washing solution S wherein the detergent D is properly
dissolved or dispersed in the water W.
The washing solution S is then introduced in the tub 3 through the
output conveying pipe 45.
A washing program performed in this washing machine 401 is shown in
FIG. 10 and differs from the washing program described with
reference to the flow chart of FIG. 8 for the fact that the
quantity Qd of detergent D together with the first quantity
Q1.sub.w of water W is introduced into the mixing tank 43 (step
116'). The washing solution S is therefore prepared in the mixing
tank 43 (step 118') by activating the recirculation mixing pump
42a. The washing solution S is then introduced in the tub 3 (step
120) through the output conveying pipe 45 and the washing program
may continue with the following phases.
FIG. 11 shows a construction variant washing machine 501 of the
laundry washing machine of FIG. 7.
This washing machine 501, as the washing machine 301 shown in FIG.
7, allows the preparation of a properly mixed washing solution
S.
The washing machine 501 comprises a mixing device 52 which is
associated to bottom of the tub 3.
The mixing device 52 comprises a recirculation mixing pump 52a, an
inlet connecting line 52b connecting the recirculation mixing pump
52a to the bottom of the tub 3 in a first zone thereof, an outlet
connecting line 52c connecting the recirculation mixing pump 52a to
the bottom of the tub 3 in a second zone thereof.
The recirculation mixing pump 52a is activated to recirculate the
liquid inside the tub 3. The recirculation mixing pump 52a
withdraws liquid from the bottom of the tub 3 via the inlet
connecting line 52b and discharges the liquid withdrawn back into
the bottom of the tub 3 via the outlet connecting line 52c.
Advantageously when the bottom of the tub 3 contains detergent D
and water W, the recirculation process allows the preparation of a
uniform washing solution S wherein the detergent D is properly
dissolved or dispersed in the water W.
FIG. 12 shows the flow chart of the washing program of the
invention performed in the washing machine 501 of FIG. 11.
The initial phases of the washing program of loading the laundry 30
(step 100) and of the washing program selection (step 110) are the
same as described above.
In a successive phase (step 116'') a quantity Qd of detergent D
together with a first quantity Q1.sub.w of water W is introduced
into the tub 3 from the drawer 6 by means of the supply pipe 9.
The quantity Qd of detergent D and the first quantity Q1.sub.w of
water W forming the washing solution S fall down and reach a level
L2 on the bottom of the tub 3.
The recirculation mixing pump 52a is then activated (step 118'') to
recirculate the liquid inside the tub 3 at the bottom thereof. The
recirculation process allows to prepare a uniform washing solution
S wherein the detergent D is properly dissolved or dispersed in the
water W.
Once the washing solution S is ready and adequately mixed, the
recirculation circuit 216 is activated (step 130) until the
complete absorption of the washing solution S by the laundry 30.
The washing program may then continue with the following
phases.
In a further embodiment, the introduction phase of a quantity Qd of
detergent D together with a first quantity Q1.sub.w of water W
(step 116'') is carried out by means of a supplemental supply pipe
54, indicated by a dashed line in the FIG. 11, which conveys the
detergent D and the water W directly on the bottom of the tub
3.
While the mixing devices above described comprise a recirculation
mixing circuit provided with a recirculation pump, it is obvious
that different kinds of mixing devices may be used, like for
example mixer devices provided with turbine blades which are
immersed in the washing solution and here adequately moved to
perform a uniform mixing.
In further embodiments, after the initial phase of placing the
laundry inside the drum and the phase of selection of the desired
washing program a phase of determining the dry weight D.sub.w of
the loaded laundry may be performed.
The phase of determining the dry weight D.sub.w of the loaded
laundry typically comprises a step of introducing a quantity of
water inside the tub to wet the laundry together with one or more
drum rotations at a pre-determined speed. The water is also
preferably re-circulated. Hence the water from the bottom of the
tub is drained to the outside. According to the measured quantity
of water introduced into the tub, the measured quantity of water
drained from the tub and the time necessary for its absorption by
the laundry, it is possible to estimate the dry weight D.sub.w of
the loaded laundry. This weight determining phase preferably
terminates with a spinning step which is intended to extract the
maximum quantity of water from the laundry, more preferably to
extract almost all the water from the laundry. A quantity of
residual water may nevertheless remain inside the laundry. After
the weight determining phase the washing program may then proceed
with the following phases as described before, namely introducing a
quantity of detergent and water or introducing a pre-wetting
quantity of water. It has to be noted that in this case the first
quantity of water or the quantity of the pre-wetting water
introduced in the tub will be adequately reduced of the quantity of
the residual water remained inside the laundry in the previous
weight determining phase. The quantity of the residual water inside
the laundry may be easily calculated by the control unit through
the measurement of the water conveyed in the tub and the water
drained from the tub during the weight determining phase.
It has thus been shown that the present invention allows all the
set objects to be achieved. In particular, it makes it possible to
reduce the quantity of water required to wash the laundry and to
reduced the power required to heat up the laundry inside and to
obtain an optimum usage of the detergent and to reduce the quantity
of detergent used compared to the known technique.
In particular, it makes it possible to obtain an optimum usage of
the detergent and to reduce the quantity of detergent used compared
to the known technique.
While the present invention has been described with reference to
the particular embodiments shown in the figures, it should be noted
that the present invention is not limited to the specific
embodiments illustrated and described herein; on the contrary,
further variants of the embodiments described herein fall within
the scope of the present invention, which is defined in the
claims.
It is underlined that the laundry washing machines illustrated in
the enclosed figures, and with reference to which some embodiments
of the method according to the invention have been described, are
of the front-loading type; however it is clear that the method
according to the invention can be applied as well to a top-loading
washing machine, substantially without any modification.
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